Detonator



Nov. 7, 1967 L. J. MONTESI DETONATOR Filed Sept. 7, 1966 INVENTOR Louis J. Monfesi United States Patent Ofifice States of America as represented by the Secretary of the Navy Filed Sept. 7, 1966, Ser. No. 578,423 5 Claims. (Cl. 102-27) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to detonating devices, and more particularly to an underwater ordnance detonating device. This invention is an improvement upon the device disclosed in U.S. Patent No. 3,169,481, issued to R.H.F. Stresau, et al. on Feb. 16, 1965.

Prior art methods for detonating underwater ordnance items have included various electrical and mechanical devices energized by the action of water pressure on diaphragms, bellows, or pistons. These devices, because of their relative complexity, have posed problems in providmg adequate safety and reliability and consequently are relatively expensive to make and require precision fabrication. When operation at shallow depths is contemplated, the need for precision operation is greatly accentuated due to the lower pressure of the explosive propagation wave along the detonating device. At shallow depths the water pressure, utilized by prior art devices as the initiating force, is low. Necessarily any pressure responsive detonating device must be highly sensitive to slight variations in pressure. The more sensitive these devices are to pressure gradations, the more sensitive they are to slight shocks and consequently premature and unwanted detonation. Thus it would be highly desirable if a detonating device could be provided for underwater ordnance items which does not rely upon moving parts, and is capable of functioning efficiently in water at various depths with a high degree of safety and reliability.

It is therefore an object of the present invention to provide a detonating device for underwater ordnance items which is ineffective in air and becomes effective merely upon immersion in water.

It is another object of this invention to provide a detonating device for underwater explosive devices which has no moving parts.

It is a further object of this invention to provide a detonating device for underwater ordnance items having a high degree of safety and reliability.

Still another object of the instant invention is to provide a detonating device for underwater ordnance items which possess the advantages of low manufacturing cost and relatively small size.

With these and other objects in view, the present invention contemplates a detonating device comprising an ignition charge, a base charge for detonating the main charge on the ordnance item, and a columnar transmission charge interconnecting the ignition charge and the base charge. The diameter of the transmission column is so chosen that it is less than the failure diameter when the column is surrounded by air and greater than its failure diameter when the column is surrounded by water. An increased safety factor is added by the provision of making the base charge into two distinct charges separated by a metal barrier to preclude accidental detonation before the device is immersed in Water. The transmission column is surrounded by a rigid tube spaced therefrom to define an annular cavity therebetween. The rigid tube is provided with a plurality of slots or apertures which serve to admit water into the annular cavity when the ordnance item including the detonating device is immersed in water. A thin plastic tube within the rigid 3,351,11 Patented Nov. 7, 1967 tube surrounds the transmission charge to prevent a direct contact of the water with the transmission charge.

Other objects, advantages and novel features of the present invention will become readily apparent upon consideration of the following detailed description when taken in conjunction with the single figure of the accompanying drawing wherein is disclosed a preferred embodiment of the present invention. 1

As shown in the drawing, the detonating device is composed of an elongate rigid metal tube 10 within which is disposed a cylindrical support sleeve 12 having a reduced diameter portion 14. Within the support sleeve 12 is an ignition charge of explosive material 16 and a priming charge 18 of suitable explosive material. Immediately adjacent the priming charge 18 and extending beyond the reduced diameter portion 14 of the support sleeve 12 is atransmission charge 20 of an explosive material such as RDX. Encasing the transmission charge 20' is a thin walled tube 21, such as Mylar, which serves to confine the explosive material of the transmission charge and to preclude direct contact of water with the transmission charge 20. Fitting within the metal tube 10 and abutting the ignition charge 16 is an electrical actuating device 22 connected to electrical leads 24 which are in turn connectable to any suitable source of a firing impulse (not shown), the specific nature of the firing impulse being dictated by the type of ordnance item in which the detonating device is to be utilized.

The opposite end of the transmission charge 20 is in cased by a thin walled sleeve 26 that extends past the transmission charge and incases an intermediate portion 28 of the base charge 30' of the detonator. The main portion of the base charge 30 is separated from the intermediate portion 28 by a metal barrier 32, formed of a material such as aluminum. This aluminum barrier 32 acts as an additional safety feature as it serves to arrest a propagation wave before the detonating force reaches the main portion 30 of the base charge. Surrounding the base charge is a metallic cup 34 that fits snugly within the tube 10 and has its end 36 flush with the tube terminus. It is this end (not shown) of the detonating device that is placed abutting the main charge of the ordnance item desired to be detonated.

By separating the base charge into two separate portions the effect of an inadvertent detonation is greatly minimized as the force and continuity of a propagation wave is interrupted by the separation of the base charge and the aluminum barrier 32.

Slots 38 are cut in the wall of the tube 10 to permit water entry into the annular space within the tube and surround the transmission charge 20, and the recessed portion 14 of the support sleeve 12 when the device is immersed in water.

The diameter of the transmission charge 20 is carefully selected such that if the device is inadvertently actuated prior to the water entering the sleeve 10 even though the transmission charge is detonated, the detonation wave will not propogate along the column between the sleeves 12 and 26 or past the aluminum barrier 32 to the main charge of the ordnance item. However, after immersion in water and the consequent filling of the annular cavity within the tube 10 the water confining the transmission charge acts as an amplifier for the propagation wave, and the detonation wave will thus have sufiicient magnitude to detonate the base charge 3% and thus activate the associated ordnance item.

From the foregoing it will be readily apparent that the present invention provides a detonating device possessing numerous advantages not found in prior art devices. The absence of moving parts enhances the reliability of the detonating device as well as greatly simplifying the manufacture and results in a reduced cost of manufacture. The provision of an aluminum barrier in the base charge and the reliance upon water to transmit a detonation wave of sufficient magnitude to detonate the base charge serves to minimize premature detonation of the device thereby increasing the safety factor.

It is to be understood that the above described arrangements are simply illustrative of the principal features of the invention. Numerous other arrangements may be readily devised by those skilled in the art to achieve similar arrangements still embodying the principles of the present invention and falling within the spirit and scope thereof.

What is claimed is:

1. A detonating device for an explosive ordnance device comprising an ignition charge,

a base charge, said base charge including a first portion and a second portion,

a transmission charge interconnecting said ignition charge and said base charge, said transmission charge having a cross sectional configuration insufficient to propagate a detonation wave when surrounded by a gas medium but sufficient to propagate a detonation wave when surrounded by a liquid medium, and

a metallic barrier separating said first portion of said base charge from said second portion of said base charge sufiicient to deter propagation of detonation waves through said base charge when said detonating device is surrounded by a gas medium.

2. A detonating device as defined in claim 1 wherein 5 said transmission charge is surrounded by a rigid tube said barrier is formed of aluminum.

References Cited UNITED STATES PATENTS 3,169,481 2/1965 Stresau et a1 102-27 20 3,209,692 10/1965 Webb 10270 3,238,876 3/1966 Allen 10 2-70 SAMUEL FEINBERG, Primary Examiner.

5 v. R. PENDERGRASS, Assistant Examiner. 

1. A DETONATING DEVICE FOR AN EXPLOSIVE ORDNANCE DEVICE COMPRISING AN IGNITION CHARGE, A BASE CHARGE, SAID BASE CHARGE INCLUDING A FIRST PORTION AND A SECOND PORTION, A TRANSMISSION CHARGE INTERCONNECTING SAID IGNITION CHARGE AND SAID BASE CHARGE, SAID TRANSMISSION CHARGE HAVING A CROSS SECTIONAL CONFIGURATION INSUFFICIENT TO PROPAGATE A DETONATION WAVE WHEN SURROUNDED BY A GAS MEDIUM BUT SUFFICIENT TO PROPAGATE A DETONATION WAVE WHEN SURROUNDED BY A LIQUID MEDIUM, AND A METALLIC BARRIER SEPARATING SAID FIRST PORTION OF SAID BASE CHARGE FROM SAID SECOND PORTION OF SAID BASE CHARGE SUFFICIENT TO DETER PROPAGATION OF DETONATION WAVES THROUGH SAID BASE CHARGE WHEN SAID DETONATING DEVICE IS SURROUNDED BY A GAS MEDIUM. 